Question

An asteroid woth mass = 1.00 x 109 kg comes from deep space, effectively from infinity, falls toward the Earth.

Find the change in potential energy when it reaches a point 4.00 x 108 m from the center of the earth. In addition find the work done by the force of gravity.

Answer 1

$\Delta U=U_2-U_1,$

$U_1=0,$

$U_2=mgd,$

$\Delta U=4\cdot 10^{18}~J,$

$A=\Delta U=4\cdot 10^{18}~J.$